Add ClearUI to Logic; Add ClearTaskView to MainGui

ClearTaskView will reset the lists that are related to the Task View.

ClearUI will clear 3 components of the MainGui: TaskView, Category,
Context.

This latest commit will allow the most updated list to reflect after a
add/edit/delete/done command.

Minor changes: Move new Logic(this) to after GUI shows.;
This ensures that the default GUI elements are in place before Logic
starts to populate the GUI.